Since the 1970's computer graphics has been a method of generating photorealistic images (see J. Foley and A. VanDam, Fundamentals of Interactive Computer Graphics, Addison-Wesley, 1982). Since that time computer graphics has been used in entertainment, advertising, and scientific data analysis. Computer graphics software depends upon an underlying model of image formation which is comprised of surface material properties, the physics of light propagation and object construction. Common computer graphic models are loosely referred to as polygonal rendering, ray-tracing (see A. Glasner, Ray Tracing, and radiosity (see Radiosity, Course Notes, SIGGRAPH 1991, Las Vegas). Each of these methods has advantages and limitations in achieving photorealism. All of these techniques, however, require data which describes the objects to be rendered.
Conventional two-dimensional color images, such as those from color photographs, have been digitally stored in a variety of digital formats. These formats differ in resolution, algorithms, color space, and bit depth amongst others. One particular format, the photographic compact disk ("photographic CD") image format used in the photographic CD system manufactured by KODAK, is a hierarchical 24-bit method based on a YCC color space. This hierarchical 24-bit method is described in U.S. Pat. No. 4,969,204 to Melnychuck et al., which is herein incorporated by reference.
In this known method, an image is scanned from film or other medium and encoded into a YCC (luminance, chrominance, chrominance) color space that is in a 24-bit format. This encoded image is decomposed into a sequence of image components in a hierarchy of decreasing resolution. The higher resolution images are used for supplying images to high-quality hard-copy devices, or to high-definition television. The lower resolution images are used for the simultaneous display of multiple images, rapidly displaying images on a standard television, etc. The various resolution versions of the image are stored on a digital storage medium, such as a compact disk.
Imaging technology, however, is capable of acquiring and recording many other types of information relating to an image other than the color of image pixels. This other type of data will be collectively referred to as "image model data", while the conventional color information will be referred to as "image data". Numerous methods exist for obtaining information about images or scenes other than the conventional color information. (A "scene" is defined as anything from which an image unit can be recorded whereas an "image" is taken to mean a conventional light recording, such as a photograph.) One such data type is range data. This geometry data of a scene can be collected by a variety of methods including laser range finding, computer-aided tomography, magnetic resonance imaging, active triangulation with coded light stripes, radar, sonar, optical disparity scanning and multiple-position photographic or motion video coupled with computer processing.
Other types of data, such as material properties of objects in an image, reflectivity or transparency of objects, different illumination of objects (such as ultraviolet or infrared), etc. can also be obtained through known sensing techniques.